| Abstract: | The effects of inhibition of glycosylation on nerve growth factor (NGF) binding and neurite outgrowth response of PC12 cells have been examined. Exposure to tunicamycin (1-10 micrograms/ml) for 24-36 hr eliminates the rapidly dissociating component of NGF binding and decreases the proportion of PC12 cells capable of elaborating neurites in a dose-dependent manner. These decreased cellular responses are probably due to an underglycosylation of the NGF receptor, since the effects of tunicamycin are correlated with a decrease in 3H-fucose incorporation rather than a general decline in cellular metabolism as measured by viability and protein synthesis. These results suggest that carbohydrate side chains are important for the function and/or orientation of the NGF receptor in PC12 cells and that the rapidly dissociating component of NGF binding may be associated with a minimum concentration of functional receptors per cell required for the full biologic response. |
